This device is used in piping system in large HVAC systems where the control of the amount of flow is desired. Currently, most controls that regulate the flow in piping systems are based on the principle shown in the quarter-turn ball valve, where the operator can have complete shutoff or full flow within a 90° turn of the handle. In the field of power assisted actuators, most all of the manufactures design them for the same quarter-turn application as well. Generally in this industry, a full port or more commonly known full bore ball valve is incorporated into the piping structures. This valve has an over-sized ball so that the hole in the ball is the same size as the pipeline resulting in lower friction loss.
There are many problems with the basic ball valve involve it's inability to regulate evenly as the valve is opened or closed. This means that simply opening the ball valve a certain percentage of the total range, say 50% for example, does not equate to 50% of the total flow of the valve. This non-linear relationship between the percentage open and percentage of flow creates problems in setting the flow into a particular section of the piping system. This is because of the shape of the insert being circular. This non-linear problem can be greatly improved with the additional of a parabolic or other characterized insert into the ball opening itself.
In the disclosed invention, a venturi tubes is used to calculate pressure differential and thus fluid flow. With a ball valve, to the nature of the throttling or jetting aspects of the ball as it rotates at low percentages of openness, it is very difficult to accurately measure flow anywhere near the valve. This leads to oversizing of the pump and running the pump at a higher pump rate to compensate for the inefficiencies of a ball valve. A venturi is used whenever low pressure loss and high accuracy is desired, and due to the nature of the valve disclosed herein, the length of straight piping is greatly reduced as the pressure differential measuring means are located directly upon the valve as this valve incorporates a venturi. Due to the low pressure loss, a venturi saves the user many dollars and frequently pays for itself in one year of continuous operation by greatly reducing pumping cost.
Other problems associated with ball valves is the amount of force necessary to open or especially close the valve when under pressure as the flow of fluid fights against the closing or opening of the valve. Especially when one is trying to barely crack open the valve to let in only a minimal amount of flow. Also, due to the characteristics of the flow opening and exit of the ball itself, at low flow rates, that is a tremendous amount of cavitation and noise exist if the pressure differential is substantial across the ball itself. The critical flow in a ball valve is encountered when delta P (the differential pressure) is 0.15 P, which is far below the usual figure of 50% of absolute inlet pressure. Another issue is the handle to adjust the opening of the ball itself, as it must be located in a position where the user can access it. In piping structures where many pipes are located and space is at a premium, the knuckles of more than one person has been wracked against the piping structure when attempting to access and adjust a ball valve. Where pressures are significant, the size and length of the handle becomes a critical aspect of the operation of the valve and the need for space can drastically increase.
The current state of the art can be found to use ceramic disks that have angular segments removed that allow for the flow of fluids. These ceramic disks are used to regulate the flow of fluids in many applications, such as high end water faucets and shower fixtures. U.S. Pat. No. 7,841,362 issued to Kim on Nov. 30, 2012 shows the use of multiple disks in a faucet or water control valve, where temperature and flow are controlled. This disclosure is typical of the faucet style of control valves, where two sources of fluid are mixed and flow is controlled. These valves have the discharge of fluid through a spout which is basically perpendicular to the flow of the fluid. Prior art does exist to detail that ceramic disks can be used to supply and discharge fluids as well as U.S. Pat. No. 7,373,950 issued to Huang on May 20, 2008 demonstrates where a single set of disks control the mixing of hot and cold water from two distinct sources and regulates the outbound flow of water through the same disks.
One of the deficiencies of the current state of the industry as well as the prior art is that a valve, that can go to complete shutoff and maximum flow with a 90 degree rotation about the axis of fluid flow, cannot also be capable of measuring the differential pressure between the inlet and outlet of the valve. Current ball valve technology, which through the use of parabolic or other inserts to the ball can approach a more linear relation between the percentage of openness of the ball to the percentage of maximum flow through the valve, does not have the capabilities to have a pre-set Cv in association with the ball valve.
Additionally, due to the surfaces upon which the fluids impact upon when the ball valve is turned and due to the close tolerances required to prevent fluids from leaking past the ball portion of the valve, it is imperative that the fluids be free from any hard impurities that can scratch or mar the surface of the ball and that can damage the exposed O-Rings. Furthermore, since the O-Rings are exposed to the fluids on a daily basis, the chance for O-Ring degradation due to reactions with the fluids is greatly enhanced, leading to failure and leakage. To prevent this possible degradation, some manufactures use Teflon seals which facilitate a sealing function as well as creating a surface with less friction than O-rings.
Another issue with using ball valves is that the user most still incorporate a venturi and high and low pressure test probes to measure the flow of the fluid. Since cavitation and throttling may occur with the use of a ball valve, the venturi must be location a sufficient distance away from the ball valve in order to more accurately measure the flow. This could cause problems in the reading and adjusting the flow in a particular section of a piping structure.
It is an object of this invention to create a device that will enable the user to adjust the flow of fluid in a piping structure where space is at a premium and where accuracy of the fluid flow is critical.
It is a further object of this invention to provide the user with a valve whose adjustment is axially relation to the flow of fluid. This axial relationship provides for a more compact unit and which more accurately controls the flow using linearly related flow control disks.
It is a further object of this invention to provide a device with which the user can measure the differential pressure as the device is being operated so that flow can be accurately measured at the actual valve as it is being adjusted. It is desirable that the space required for this measurement be compact in nature and close to the body of the valve for the most accurate measurement as well as being compact for the tight spaces that it will likely be experiencing.
It is a further object of this invention to provide an embodiment of this device where be a Cv can be set for this valve, through the use of flow control disks, whereby the user has an axially controlled valve with a set maximum Cv, said valve being able to go to complete shutoff.
Accordingly, it is the goal of this invention to create an adjustable valve that is axially related to the fluid flow, containing port to determine the actual flow of the fluid, that has the aforementioned characteristics of simplicity, accuracy, adaptability to current uses and safety.